Knife-blade switch



H.. E. LEPPERT KNIFE BLADE SWITCH Jan. 5 1926.

Filed Oct. 6, 1924 INVENTOR the following is a specification.

Patented 5,' 1926 UNITED sTATEs PATENT OFFICE.

BENNY E. IQEPPERT, 01' NEW BRITAIN, CONNECTICUT, ASSIGNOR TO THE TRUMBULL ELECTRIC MANUFACTURING COMPANY, OF PLAINVILLE, CONNECTICUT, A CQB- PORATION OF CONNECTICUT.

KNIFE-BLADE swrron.

Application filed October -6 To all whom it may concern:

Be it known that I, HENRY E. LEVPPERT, a citizen of the United States of America, residing at N ewBritain', Hartford County, State of Connecticut, have invented 'a new and useful Knife-Blade Switch, of which My invention relates particularly to quick-break switches of the so-called safety type. Such constructions frequently have hinged blades mounted upon an insulating base of slate or porcelain and are provided with a handle for manualoperation and mechanism for making and breaking a circuit with a snap action out of the control of the operator. When such switches are operated there is an essential shock and jar which tends not only to loosen the parts but sometimes even to break them.

The main object of myinvention is to prevent such injury. S ecifically I have sought to provide a simp e and inexpensive construction embodying switch jaws having a buffer which can be readily applied to standard type switches. v

Another object is to rovide a formof bufl'erwhich can be rea ily replaced or renewed; 4

The accompanying single sheet drawing illustrates the preferred form of my invention and also some modifications.

Figure 1 is a perspective View of a safety switch construction embodying one form of various the invention. c

Figure 2 is a fragmentary side view and partial section of the principal parts of the construction..

Figure 3 is a fragmentary end view looking at the construction shown in Figure 2 from the left.

Figure 4 is a perspective view showing the (parts of, aiswitch jaw and buifer se liiarate g I igures 5 and 6 are side views showing diiferent ways of securing a butter to a switch .j-aw. r j

In the standard type construction illus& trated, thereis a stationary post-10, sta tionary spring jaws 11, and a blade 12 hinged to the post 10 and adapted to engage between the jaws 11. These parts are usually supported by an insulating base 13 formed of slate or porcelain.

The switchv mechanism per .se is mounted 1924. Serial No. 741,787.

in a suitable manner in some form of box or receptacle 14 usually of steel. The invention is applicable to a switch having any number of blades. In the form shown the operating crank 15 is pivotally supported in the box and provided with an external operating handle 16. The operating crank 15 'is connected to the switch blades in any in any well'known or satisfactory manner.

A butter 21 is secured to the jaw member 11 in a osition to receive the impact ofthe ,knife b ade 12 in its circuit closing move- 'nient. This buffer is preferably formed of hard fibre or similar material with its ain running transversely tothe knife bla so that the shock of the blade and attached parts will not be likely to split or chip it.

This bufler'is secured to' the jaw member 11 for instance by means of a member 22 which extends into the buffer member and is locked to the jaw member. One end of the member 22 may have teeth 23 so that it ma be readily driven into the buffer but Wlll not accidentall work loose, The other end is secured to the jaw member, for

instance by means'of a pin or. rivet 24 which extends through the o ening 25 of the jaw member and interloc s in a notch 26 in the connector 221-} The parts are so shaped and proportioned that when assembled the buffer rests on the base 13 and against the edged the jaw member 11 and its foot 27, as shown Figure 2; The jaw member is secured tothe base 13 in the usual manner, for instance by one or more screws 28. The

parts may be "proportionedso that the bufier receives the impact not only of the blade 12 but of the bracket 19 so that the shock and strain are more widely distributed and therefore less likely to injure the bufier or base. Should the buffer be broken or become worn it is a ve simple matter to r move the 'pin 24 R an the jaws become worn-or injured a new; set

insert a new buffer; the cost of which is insignificant. Should its with a fresh bufi'er attached. can be substituted. 1

In the form shown in Figure 5 the bufier-x is secured to the jaw member by an ordinary screw 30 whose head fits against the edges of the jaw member to hold it in place.

In the form shown in Figure 6 the buffer is connected to the jaw member by means of a staple 32 and the pin 24.

The member 22, or whatever other form of holding member may be substituted therefor, is preferably a little less in thickness than the space between the jaw blades so that the necessary spring of the jaws is not affected by the addition of the buffer member. Also the parts are so proportioned that the buffer member has a slight freedom of movement so that the full impact of the knife blade 12 against the buffer member is not transmitted to the jaws.

Obviously this construction permits the contact jaw member 11 and its base 27 and the buffer 21 to be assembled and sold as a unit which is of considerable advantage to the trade. This feature also facilitates the factoryassembly of the switch. A point of great importance is that the spring of the jaws is not affected by any amount of battering or wearing of the buffer member.

It will be seen that this simple type of buffer construction is adapted to be readily applied to almost any type of knife blade switch without requiring any material modifications in the standard blades and switch jaws. The use of such buffers not only materiallyfprolongs the life of the switch but decreases the noise of operation.

I claim:

'1. A knife switch contact including spaced contact jaws, a stop block member and link means loosely connecting said block member with said jaws to retain said block member in fixed position adjacent said jaws but entirely outside of the space between said spaced jaws.

2. A knife switch including spaced contact jaws, a foot supporting said jaws, a stop member for receiving the impact of a cooperatin knife switch blade, and means for securing said stop member alongside said awe and said foot, the said stop member be-- ing positioned outside of the space between the said jawsso that the spreading of said stop member will not spread said jaws.

3. In a knife blade switch, a switch base, a hinge post and a contact jaw onsaid base, a switch blade pivoted to said hinge post, and. an insulating stop block mounted on said base between said hinge post and said eeaeve ed on said base, a switch blade pivoted to the hinge jaw and a fibrous bufier block to receive the closing impact of said switch blade, the said buffer block being mounted on the surface of the base adjacent to said contact jaw and havin an anchor member connecting said buffer %lock with said contact jaw to retain said bufi'er block in position so that the spreading of said block will not spread said jaw.

5. In a knife switch contact, yielding switch jaws spaced apart, an anchor member secured to said jaws and a fibre stop block secured to said anchor member, the said stop block being positioned to receive the impact of a co-operating switch blade without spreading said jaws and said anchor member being positioned to be entirely clear of the path of movement of the said switch blade.

6. In a knife blade switch, spaced jaw members adapted to receive the knife blade of the switch, a nonmetallic buffer member and a connector having teeth secured in said buffer member, and having a shank secured between said jaw members.

7 In a knife blade switch, a switch base, a pivoted switch blade mounted on said base, a contact member mounted on said base and having contact jaws spaced apart and a buffer member secured to said jaws and supported directly upon said base and being positioned in line with the space netween said contact jaws and entirely outside of said space.

8. In a knife switch contact, a pair of yielding jaws, a buffer member outside but adjacent the edge of said jaws, a connector having one end secured in said buffer and the other end extending between said jaws and rivet means for securing said connector to said jaw members.

9. In a knife switch contact, a pair of yielding jaws, a bufier member closely adjacent the edges of said jaws, a connector secured to said buffer and extending between said jaws and means extending through said jaws for securing the parts together as a unit.

HENRY n. LEPPERT. 

